thanks for the replay HunterD. I had changed all of the oil myself 3000 miles ago so it was fairly new. I believe they were big enough metal pieces to cause concern. I’ve been really easy on my Monty. I know to only drive it in 4H on paced roads as that keeps the diffs open. so one thing I may have explained incorrectly earlier. Contrary to what I originally thought about my issues being the transfer case, the shop mentioned nothing about the transfer case at all and said it was purely the front differential causing the vibration. Not sure if that changes anything but I think you may have thought I needed a t-case instead of a front differential. I’m also having a shop who did my OME lift give me a second opinion! Cheers man

 

That’s kind of a good idea considering how expensive used parts are individually. I’m seeing some used front differentials on eBay and such for only 200 - 400 dollars though. I guess it’s always risk but it could be worth a try. How difficult is changing the front differential? Is it something I could do with a couple buddies?

 

Sorry, my bad. You had pictures of the transfer case leaking and my brain was still stuck on transfer case... If the issue with the front differential, then driving in 2wd only should be OK, since this disconnects both sides of front half axles and front drive shaft. Nothing in the differential should be moving at that point. You can of course rebuild front diff. The problem is - you are not going to know what parts you need until you open it up, examine and measure everything. Might be a fun project. I've never done one myself on Montero, so i can't tell you how easy or difficult it might be, but I'm 100% certain it is totally doable. Best of luck if you decide to undertake this adventure. Keep us updated here on your progress

 

Pic of front diff with skid pans off: I think it would be a pretty straight-forward job to take it out and replace with a used one.....might be cheaper than rebuilding. And if you got a used one from a Montero that wasnt off-road much, then Im sure it would be in good shape.

 

If you get a used one from a junk yard, you can just disconnect at half-axle connectors (4 bolts on each each side), plus drive shaft and you are half way there.

 

Hunter.....yea, it looks like a fun weekend job to do.

 

thanks man that gives me a bit more confidence to tackle this thing! 😎 The search for a used diff is on.

 

That doesn’t sound too bad at all... I’ll have to do some homework on removal and then start searching for a used one. Thanks Hunter

 

So I finally got new differentials installed and since I went to 33” tires I decided to switch both differentials from 4.3 to 4.9 to bring my final drive ratios closer to stock. Found a good deal from a local junkyard.

I’m glad I didn’t pay that other shop $2400 to rebuild my front diff because with these totally new diffs, The vibration issue is still exactly the same.

I have no idea where to go from here, but I know I can’t have this truck vibrating & leaking transfer oil when I’m out in the mountains. Or break another drive shaft... So my thoughts are: it is either the angle on the driveshaft that is causing some binding, or there Is an issue with the transfer case (bearing or something). Can someone tell me what exactly spins & moves in 4wd that doesn’t spin in 2wd? (From the transfer case to the front wheels). I can’t believe it’s been this hard to track down this vibration that only occurs in 4wd. I’m not giving up though. I almost want to get a cheap camera to mount under there and investigate haha. Oh and here’s an updated pic With the 33’s thanks guys!

 

Christo.......As I was reading your post, I was thinking "maybe you could borrow someone's small digital camera and mount it underneath and videotape what is going on as you drive", and you made the same comment. I think that might help solve the problem of knowing where the issue is coming from.
Good luck with it.......your bound to find the issue soon.
Nice looking Monty with those 33s.
Hey......how about engine mounts? Is it possible that you have a bad motor mount and that with 4x4 engaged, it puts enough force on the transfer case to cause the vibration???? Just a wild thought.